Cytomegalovirus peptide–Major Histocompatibility Complex (CMV pMHC) (CMV pMHC)

Cytomegalovirus (CMV) peptide–Major Histocompatibility Complex (pMHC) complexes are specialized molecular structures displayed on the surface of cells infected with Human Cytomegalovirus (HCMV). These complexes are formed when viral proteins, such as the tegument protein pp65 or the immediate-early protein IE1, are processed into short peptides and loaded onto MHC Class I molecules for presentation to the immune system (Stern et al., 2019). Once on the cell surface, the pMHC complex serves as the primary target for recognition by the T-cell receptors (TCRs) of CD8+ cytotoxic T lymphocytes, which is essential for controlling viral replication and maintaining latency (Halenius et al., 2015). In immunocompromised patients, such as those undergoing hematopoietic stem cell or solid organ transplantation, the absence of effective pMHC recognition can lead to life-threatening CMV reactivation. Consequently, these complexes are major targets for advanced immunotherapies, including adoptive T-cell transfers and engineered TCR-T cells designed to specifically eliminate infected cells (Schmitt et al., 2017). However, the virus has evolved sophisticated evasion mechanisms, such as the expression of US2 and US11 proteins, which trigger the degradation of MHC molecules to prevent pMHC surface expression and subsequent immune detection (Halenius et al., 2015).

Other names

HCMV peptide-HLA complexCMV antigen-MHC complexCMV-specific pMHCHLA-restricted CMV peptidespp65-HLA complexIE1-HLA complex

Targeted cell lysis via T-cell receptor (TCR) or TCR-mimetic recognition of viral peptides presented on MHC molecules, leading to the activation of cytotoxic effector functions (Schmitt et al., 2017).